ICC Commercial B2 key terms

The process of assigning a building or portion of it to a use group based on the character of the activities expected inside, which then sets allowable height, area, egress, and fire protection requirements.

A lettered category such as A, B, E, F, I, M, R, S, or U that groups buildings by hazard and function, controlling which code provisions apply to each part of a structure.

A building containing two or more use groups, either separated by fire barriers that allow each part to be treated independently or treated as a single nonseparated occupancy with stricter overall limits.

A space of a secondary function, such as a boiler room or storage room, that is accessory to the main occupancy and must be separated from it by fire-resistant construction of a specified rating.

The classification, Type I through Type V, describing how much fire resistance the structural frame, exterior walls, and floor and roof assemblies must have, with subtypes A and B for noncombustible types.

The maximum floor area permitted per story, found in a table indexed by construction type and occupancy, then adjusted for frontage, sprinklers, and multistory conditions.

The maximum number of stories and feet above grade permitted for a given construction type and occupancy, determined from tables and modified by automatic sprinkler protection.

An allowance that increases permitted building area when the building perimeter faces a public way or open space of adequate width, rewarding sites with more accessible exterior exposure.

An intermediate level within a room or story, limited in area relative to the floor below, that is not counted as a story and is treated as part of the space it occupies.

The area within the surrounding exterior walls of a building or portion of it, used in calculations of allowable area, occupant load, and other code thresholds.

The total number of persons a space is designed to hold, calculated by dividing floor area by a use-specific factor or by counting fixed seats, and used to size exits.

A continuous and unobstructed path of travel from any point in a building to a public way, comprising the exit access, the exit, and the exit discharge.

The portion of the egress path that leads from the occupied space to an exit, including aisles, corridors, and the travel distance before reaching a protected exit.

The portion of the egress system between the exit and the public way, often a lobby, vestibule, or exterior court that must remain open and unobstructed.

The measured length along the natural path of travel from the most remote point in a space to an exit, limited by occupancy and sprinkler protection.

The distance a occupant must travel before reaching a point where two separate routes to exits become available, limited to keep single-direction travel short.

The clear width of an exit component, sized by multiplying occupant load by a capacity factor, with minimums for corridors, stairs, and doors.

A continuous, unobstructed path connecting accessible elements and spaces, complying with slope, width, surface, and change-of-level requirements so people with disabilities can use the building.

A path of travel usable by persons with disabilities, including areas of refuge and accessible routes to them, required where the building is not fully sprinklered or otherwise exempted.

A space protected from fire and smoke where persons unable to use stairs can wait for assistance, typically adjacent to an exit stairway and equipped with two-way communication.

The period, in hours or fractions of an hour, that a building element resists fire exposure when tested to a standard fire test, expressed on assemblies and structural members.

A fire-resistance-rated wall assembly, continuous from floor to floor or roof, designed to restrict the spread of fire and typically used to separate occupancies or exit enclosures.

A fire-resistance-rated wall with a lower rating than a fire barrier, used to separate dwelling units, guest rooms, or corridors from other spaces within a story.

A continuous membrane or assembly designed to resist the passage of smoke, used to protect means of egress and smoke compartments in occupancies such as health care and malls.

A space enclosed by smoke barriers so that smoke migration is limited, allowing occupants to relocate horizontally to a protected zone during a fire.

The rating of wall and ceiling materials as Class A, B, or C based on flame spread and smoke development in a standard test, with limits varying by occupancy and location.

A numerical result from a standard surface burning test that ranks how quickly flames spread across a material, used to assign interior finish classes.

A numerical result from the same surface burning test measuring how much smoke a material produces, used alongside flame spread to classify interior finishes.

The columns, girders, beams, trusses, and other members that support floors and roofs, required to have fire resistance based on the building construction type.

The load produced by occupancy and use, including people, furniture, and movable equipment, assigned values by occupancy in the structural design provisions.

The permanent weight of the building itself, including structure, finishes, partitions, and fixed equipment, that the structural system must carry throughout its life.

Prescribed ways of adding dead, live, wind, seismic, snow, and other loads together with factors to ensure the structure performs safely under realistic worst cases.

The system of footings, piles, mats, or walls that transfers building loads to the ground, designed using soil bearing capacity and settlement considerations from a geotechnical report.

The widened base of a foundation element that spreads structural loads over a larger soil area to keep bearing pressure within allowable limits.

The maximum pressure a soil can safely support, usually established by geotechnical investigation and used to size footings and other foundation elements.

The exterior shell of a building, including walls, roofs, windows, doors, and foundations, that separates conditioned interior space from the outdoors and controls heat, air, and moisture.

The boundary of the conditioned space, defined by insulation, glazing, and sealed assemblies, that determines where energy code requirements for heat transfer apply.

A measure of how readily an assembly conducts heat, equal to the inverse of its R-value, used in energy code tables to limit heat loss through walls, roofs, and windows.

A measure of thermal resistance, indicating how well a material or assembly slows heat flow, with higher values meaning better insulating performance.

A continuous system of materials that resists uncontrolled air leakage through the building envelope, required to be sealed and verified in energy code compliance.

A material installed to slow the movement of water vapor through building assemblies, placed according to climate to reduce condensation and moisture damage.

A device that automatically adjusts artificial lighting output in response to available daylight, required in certain spaces to reduce energy use.

The maximum permitted lighting wattage per unit of floor area, used by the energy code to limit installed lighting power in buildings and spaces.

A control that turns lights off or reduces them when a space is unoccupied, required in many rooms as part of energy code lighting controls.

Building elements outside conventional scope, such as membrane structures, towers, and pedestrian walkways, governed by dedicated code chapters with their own criteria.